A flow switch is a device that can sense actual fluid flow, rather than pressure, in a piping system. Using a flow resisting disc and spring, they can be set up to detect increasing flow, or decreasing flow. Examples of this could be a rupture or leak in a system which could trigger an alarm showing flow rates above the normal range.
A decrease in flow would occur with clogged filters, or line obstructions.
Manufactured in Stainless Steel, with Schedule 40 or Schedule 80 pipe sections, they can handle all pressure ratings of that piping system. Pressure drop is about the same as using a 90 degree elbow in the line.
Contacts of the flow sensors are rated at 20 VA, 120 VAC, as standard, and are of SPDT configuration, offering one normally closed, and one normally open contact.
A 1/2” NPT fitting for attaching a Junction Box is standard, and the UL3266 #20 leads are 18” in length.
Flow switches in our standard line are constructed of either 304, or 316 SS pipe sections 5” in length.
The internals are of 316SS on all models, including the operating spring. The operating disc is laser trimmed acetal resin, or SS on special order.
The disc assembly rides on a Teflon shuttle, secured with SS hardware. This assembly is made to order to accommodate the various flow rates customers require.
A protective mylar label displays S/N, P/N, and Model of Flow Switch.
As is the case with all products from National Magnetic Sensors, variations are not a problem for us to provide for our customers.
Loss of fluid can be catastrophic in many instances. Cooling systems, whether fixed such as rooftop coolers and HVAC systems, or mobile, such as in heavy equipment cooling systems, all need monitoring to insure safe operation. Lubrication systems are another important area where a loss of lubricant can destroy bearings, engines, gears, actuators, and numerous other devices.
These systems needing flow switches are wide ranging from factory usage, to the entire transportation industry, including ground support at many air terminals.
Marine applications abound on large diesel engine cooling systems.
While our Liquid Level Sensors assure a supply of these important fluids, our Flow Switches make sure these fluids arrive at their intended destinations with interruption.